PHP 5.2.1 Release Announcement

The PHP development team would like to announce the immediate availability of PHP 5.2.1.
This release is a major stability and security enhancement of the 5.X branch, and all
users are strongly encouraged to upgrade to it as soon as possible.

Extended filter extension support for $_SERVER in CGI and apache2 SAPIs.

The majority of the security vulnerabilities discovered and resolved can in most cases be only abused by local users and cannot be triggered
remotely. However, some of the above issues can be triggered remotely in certain situations, or exploited by malicious local users on shared hosting setups
utilizing PHP as an Apache module. Therefore, we strongly advise all users of PHP, regardless of the version to upgrade to 5.2.1 release
as soon as possible. PHP 4.4.5 with equivalent security corrections is available as well.

The key improvements of PHP 5.2.1 include:

Several performance improvements in the engine, streams API and some Windows specific optimizations.